I think a third more plausible answer is that the companies in question are simply sending ultra cheap junk to random addresses in the USA as a way to pad their perceived business. This has been going on for years.

see:

https://www.wsj.com/articles/fake-orders-brush-up-online-sal...

https://www.forbes.com/sites/wadeshepard/2019/10/25/american...

Wow. But doing this with seeds is terrible. It has the potential to boycott the economy at national scale.

There are more than 230 viruses of useful plants that can be transmitted by seeds, and hundreds of invasive species... How can this packages be allowed to cross several frontiers and enter in a country?

it can be allowed by conforming to phytosanitary proceedures, this means inspection and permits. This is common and regular proseedure for agri/horti culture

I assume that you can not obtain a permit if the origin of the alive material can't be verified, the sender is not identified, and unless somebody has paid for the permit (they aren't cheap).

Moreover, anybody that would send a package like those shown in the article, to an address in Florida, California, Arizona or Texas would be violating the Citrus quarantine, therefore commiting a crime.

And to finish, flooding frontiers with thousands of small packages of time consuming cheap material is evil. I assume that messing deliberately with the work of civil servants or slow customs is also typified as a crime.